Devices for deflecting the jets produced by jet engines



1961 ARLETTE MARCELLE MlHAlL 2,997,844

NEE GROUSSET ETAL LECTING THE JETS PRODUCED BY JET ENGINES 2 Sheets-Sheet 1 DEVICES FOR DEF Filed June 8, 1960 Alt 54172145 4 4 p 7 9 m m 2 m E m J m A D mmm mm E R LT Ra csm H Mam E N T I TEM E R A Aug. 29, 1961 DEVICES FOR DEF Filed June 8, 1960 2 Sheets-Sheet 2 lla/r44;

United States Fate $997,844 DEVICES FOR DEFLECTING THE JETS PRODUCED BY JET ENGINES Arlette Marcelle-Mihail,-ne Grousset, Asnieres, Seine, Jean Paul Tochon, Saint-Cloud, Seine, Henri Turinetti, Paris, and Ernest Marie Ren Dubois, Fontenay-Aux- Roses, Seine, France, assignors to Societe Nationale dEtude et de Construction de Moteurs 'dAviation, Paris, France, a company of France Filed June 8, 1960, Ser. No. 34,754 Claims priority, application France June 17, 1959 1 Claim. (Cl. 60-3554) It has previously been proposed to provide devices for deflecting the jets produced by jet engines, wherein the path of the deflected jet is delimited by guide members which extend parallel to the axis of the discharge nozzle and which are arranged relatively to one another in such manner as to reduce the divergence of the streams of the deflected jet, so that the latter remains sufficiently compact and contained to exert a substantial thrust which can be either negative (braking counter-thrust) or directed in any direction relatively to the axis of the normal jet.

In embodiments of the said prior devices, the said guide members, which can be constituted of specially profiled members, are associated with deflecting vanes situated downstream of the discharge nozzle peripherally of the normal jet flow, the deviation being initiated by means of a diametral interceptor or obstacle arranged at the outlet of the discharge nozzle.

We have found that a straight or slightly curved interceptor of this kind as shown at 1 in FIGURE 1 of the accompanying drawings, extending along a diameter of the circular discharge nozzle 2 does not, in the absence of suitable guide members make it possible to obtain a deflected stream which is perfectly uniform in force and direction. In fact, in the regions A-A and BB situated about 45 from the plane CC of the interceptor, there are formed zones of greater speeds than those in the zone situated in the plane DD situated at 90 from the plane of the interceptor. FIGURE 1 also shows a diagram of the speed range at the outlet of the grid of vanes shown at 3 in FIGURE 2 of the accompanying drawings.

When the diametral-obstacle jet reverser is used on an aircraft fuselage of conventional type, the presence of zones of excess speed in 45 planes can have a detrimental influence on the flow about the empennage E and, in the case of certain shapes, may interfere with the tailplanes situated near the deflected stream, as FIG- URE 2 shows clearly.

The present invention is concerned with improvements in the guide members of the said prior devices, with a view to eliminating detrimental overspeed zones as defined hereinbefore, whilst retaining a good efficiency for the deflecting device as a whole. These improved guide members are intended to canalise the deflected stream so as to direct it towards the plane DD perpendicular to the interceptor 1.

According to the present invention, the guide members are constituted by curved profiled members whose concave faces towards the interior of the deflected stream-that is to say towards the plane DD and whose convex consequently faces towards the exterior of the said stream.

The guide members may be hollow vanes provided with blowing nozzles adapted to impart a rotary mve ment to the jet so as to counteract the rotational movement which it may have been previously given.

7 ing arrangement.

2 "The invention is illustrated by any of the examples in the accompanying drawings, in which:

FIGURES 1 and 2 are diagrams already referred to above;

FIGURE 3 is a diagrammatic view of the rear of a discharge nozzle equipped with-improved guide members;

FIGURE 4 illustrates the asymmetry due to the rotation of the jet;

FIGURE 5 shows an. improvement intended to combat this asymmetry, and

FIGURES 6a and 6b are explanatory diagrams illus' trating how the invention operates.

The guide members shown at 4 in FIGURE 3, which extend parallel to the axis of the discharge nozzle 2, are constituted by curved profiled members whose concavity is directed towards the mean plane DD of deflection. These profiled members, three in number in each quadrant in the examples shown in the drawings, occupy sectors ab and c-d of the periphery of the normal non-deflected jet issuing from the discharge nozzle.

In the sector situated between b and c, the deflected jet is canalised solely by the grid of vanes (not shown); on the contrary, in sectors a-b and cd, it will be canalised both by the grid of vanes and by the profiled members 4 whose oifset is such that they produce a convergent effect on the flow between b and c.

The circulation between the profiled members 4 is effected by an ejector effect, in cascade with respect to the main flow of the deflected stream.

In the case [of a turbo-jet engine, the jet is given a rotational movement in one direction or the other relatively to the axis of the discharge nozzle depending on whether the speed is lms than or greater than the matching speed of the turbine. Therefore, the deflected jet is asymmetrical relatively to the plane C-C of the interceptor, as illustrated in FIGURE 4. The mean plane F-F of the deflected stream is inclined at an angle a relatively to the plane D-D perpendicular to the interceptor. This asymmetry has the result of subjecting the fixed surfaces of the empennage E and also the rudder control surfaces to different loads.

The present invention makes it possible to efiect not only the reconvergence of the deflected jet described hereinbefore but also correction of the asymmetry illustrated in FIGURE 4. This correction is obtained by a suitably directed blowing arrangement, taking into account the direction of rotation of the jet.

For this purpose, the longitudinal guide members are constituted by hollow vanes 5 (FIGURE 5) equipped With a blowing slot 6 situated in the vicinity of the trailing edge and adapted to be supplied by a take-off from the compressor of the jet engine. The intensity of the discharge from the slots 6 can be adjusted by means of a valve interposed in the supply circuit.

If the jet has been previously given a rotary movement in the direction of the arrow 1, (FIGURE 6a), the hollow vanes 5a situated in the plane B-B will be supplied with compressed air in order to counteract this rotational movement. On the contrary, if the first rotational movement is in the direction of the arrow f (FIGURE 6b), the vanes 5b in the plane A-A will have to be supplied.

It should be noted that the device corrects by itself, to a considerable extent, the efifects due to the rotational movement of the jet without the aid of the auxiliary blow- The guide vanes in fact are of increased effectiveness when they are situated in a zone of overspeed, since the fluid which they deflect towards the horizontal axis D-D is given a greater momentum relatively to the vanes situated in the plane arranged at from the first-mentioned vanes. This increased effectiveness makes it possible to limit the overspeed zone to an acceptable angle.

We claim: bers for imparting a rotary movement to the substantially In a jet propulsion engine having a thrust-providing arcuate radially deflected jet guided by said members, nozzle of substantially circular cross-section, a jet deflectabout said axis. ing device comprising controllable means for directing the jet issuing from said nozzle substantially radially with re- 5 References Cited in the file of this Pawnt spect to the nozzle axis, about a diametrical plane of UNITED STATES PATENTS said nozzle, a plurality of hollow vane-shaped guide mernbers extending substantially parallel to said axis for degmlth et g i' i" limiting the path of the deflected jet, said vane-shaped mwn members having concave surfaces facing toward said 10 FOREIGN PATENTS diametrical plane and convex surfaces facing away there- 7 5 4'065 Great Britain 1, 1956 from, and fluid blowing means on said vane-shaped mem- 

